1. Field of the Invention
The present invention relates to a substrate treating method and substrate treating apparatus in which a treating solution is used to treat a substrate and which are particularly for use in performing a cleaning treatment subsequently to a developing treatment in a process of manufacturing a semiconductor device.
2. Description of the Related Art
When a semiconductor device, liquid crystal display device, and electronic circuit component are manufactured, a substrate is subjected to a developing treatment and thereafter successively subjected to cleaning and drying treatments so as to form a pattern in a process of forming a circuit including a device, wiring, and the like.
A manufacturing process of the semiconductor device first comprises: forming a film to be processed (e.g., an insulating film, conductive film for wiring), and a photosensitive photo resist film on a semi-conductor substrate in a known method. Thereafter, this photo resist film is subjected to the developing treatment. Here, as well known, after a predetermined pattern is projected/exposed in the photosensitive photo resist film on the semiconductor substrate via a reticle for exposure, a developing solution is supplied to form the pattern.
After the developing treatment is performed, the developing solution, a dissolution product generated during the developing treatment, and micro particles remain on the surface of the semiconductor substrate. When so-called impurities and contaminants are left in this manner, in a process of using the pattern of the photo resist as a mask to subject the film to be processed (e.g., the insulating film, conductive film forming a material of a wiring layer) to etching processing, an error of dimension is generated, and yield drops in the manufacturing of the semiconductor device.
Therefore, it is necessary to successively perform the cleaning and drying treatments, bring the surface of the semiconductor substrate into a clean state, and remove the remaining developing solution, dissolution product generated during the developing treatment, and micro particles.
A related-art cleaning method comprises: rotating the substrate at a high speed; discharging the cleaning solution via a fixed nozzle; passing the cleaning solution toward a peripheral edge from a middle portion; and replacing the developing solution with the cleaning solution to stop the progress of development reaction. Moreover, the method further comprises: washing away and removing the developing solution, dissolution product generated during the developing treatment, and micro particles from the substrate.
In recent years, technical developments such as miniaturization and high integration of the semi-conductor device and bore diameter enlargement of the semiconductor substrate have been performed. When the bore diameter of the semiconductor substrate is enlarged, that is, when an area of the substrate increases, many problems are generated in using the related-art cleaning method.
A discharge port of the nozzle is disposed and fixed in a position above the middle portion of the semiconductor substrate. Therefore, a degree of replacement of the developing solution increases in the middle portion directly contacting the cleaning solution discharged from the nozzle and in the vicinity of the portion on the semiconductor substrate, the dissolution products and micro particles are also effectively removed, and a cleaning effect is enhanced.
However, the peripheral edge of the semiconductor substrate is not directly hit by the cleaning solution with a sufficient pressure, and is low in the cleaning effect as compared with the middle portion of the semiconductor substrate and the vicinity of the portion. Therefore, in the peripheral edge of the semiconductor substrate, a part of the developing solution remains without being replaced, the dissolution products and micro particles are not completely removed and remain, and so-called cleaning spots are generated.
Moreover, in the related-art cleaning method including the drying treatment, the substrate is rotated at a high speed. Therefore, with the enlargement of the bore diameter of the substrate, a physical load is further added, and the pattern of the photo resist formed by the developing treatment is adversely influenced.
For example, when the substrate having a large bore diameter of 300 mm or more is used to manufacture the semiconductor device, the peripheral edge of the semiconductor substrate is influenced by a centrifugal force and cleaning solution flow. A phenomenon remarkably occurs in which the pattern of the photo resist formed by the developing treatment is damaged or pattern falling is generated. Thereby, it is necessary to perform the cleaning and drying treatments without rotating the substrate after the developing treatment.
With the miniaturization of the dimension of the semiconductor device, the developing solution does not sufficiently permeate between the patterns in a related-art developing method, and therefore non-uniformity of a local pattern dimension in a chip raises a problem. Moreover, with the bore diameter enlargement of the substrate, in the related-art developing method, the non-uniformity of the pattern dimension in a substrate plane is caused, and a large problem occurs.
Additionally, in general, alkaline aqueous solutions such as tetramethylammonium hydroxide (TMAH) are used as the developing solution of the photo-sensitive resist in the manufacturing process of a semiconductor. Since the developing solution is an aqueous solution, wettability to the photosensitive resist surface having a hydrophobic nature is not sufficient. Therefore, when a reaction product generated as a result of neutralization reaction is in the vicinity of the surface, the developing solution is not easily diffused between the reaction product and photosensitive resist surface, and alkali ion concentration locally differs. As a result, it has been observed that a developing rate differs with a position.
For example, there are a pattern disposed in a broad dissolution region and a pattern disposed in a region whose periphery is hardly dissolved. In this case, for the pattern disposed in the broad dissolution region, an amount of reaction products present in the vicinity of the pattern is large, the developing solution is not easily diffused between the reaction product and photosensitive resist, and the progress of the development is inhibited. There is a problem a line dimension becomes large (dimensional difference of a coarse/dense pattern) as compared with the pattern disposed in the region whose periphery is hardly dissolved.